This invention relates to retaining walls for stabilizing inclined land surfaces. More particularly the invention relates to modular retaining walls in which tiers of header members extend into structural backfill material and support stretcher members which extend horizontally between the header members and which form the front face of the wall.
The weight of the backfill material behind the face of a retaining wall creates a load force which becomes progressively greater at greater depths within the backfill. The load force is increased by roadways and vehicles or structures which may be situated on top of the backfill. The load force is primarily directed downward against subsoil but also has a horizontal component which must be sustained by the wall.
One known type of retaining wall has a modular construction which includes spaced apart columns of precast concrete header members which extend from the front face of the wall into the backfill material. The front face is formed by precast concrete stretcher members which extend horizontally between the headers and which are supported by the headers. Compacted backfill extends between the headers to the back surfaces of the stretcher members. Thus the stretcher members of the prior wall constructions must be sufficiently massive to sustain the horizontal component of load force in the backfill. The prior stretcher members also partially support the weight of overlying headers and must also be sufficiently massive for this purpose.
Retaining walls can be more attractive if landscaping plants are grown on the face of the wall. The prior wall constructions described above are not particularly conducive to plantings. While a strip of the backfill is exposed at each tier of the wall, it is undesirably narrow for planting purposes because of the shape, bulk and location of the load force resisting stretcher members. Further, the compacted backfill material which is exposed at the face of prior modular retaining walls may not be well suited for the growing of plants.
Header members of some prior modular retaining walls are linked together by thin projecting ribs which extend upward from the top of each header between spaced apart ribs on the bottom of the overlying header. The projecting ribs are relatively fragile portions of the headers which are susceptible to damage during construction of the wall. The ribs also allow forward or backward displacement of the header members relative to each other rather than establishing and maintaining a uniform batter or inclination of the face of the wall.
The present invention is directed to overcoming one or more of the problems discussed above.
In one aspect the present invention provides a retaining wall for stabilizing compacted structural backfill. A plurality of spaced apart columns of header members extend into the compacted backfill from a front surface of the backfill and also extend out from the front surface of the backfill to a front face of the wall. Front ends of the header members have inclined arms which extend outward and upward at the front face of the wall. A plurality of horizontal stretcher members extend between the header members at the front face of the wall and are supported by the inclined arms of the header members. The retaining wall further includes a plurality of vertically spaced layers of geosynthetic mesh reinforcement extending between the columns of header members and extending backward into the compacted backfill from the front surface of the backfill. The layers of geosynthetic mesh reinforcement have forward ends which turn upward at the front surface of the compacted backfill and then extend back into the compacted backfill. A volume of planting soil is disposed between the stretcher members and the upturned forward ends of the layers of geosynthetic mesh reinforcement and forms exposed tiers of planting soil at the front face of the retaining wall.
In another aspect the invention provides a retaining wall for compacted structural backfill wherein the retaining wall includes a plurality of cast concrete header members stacked in spaced apart vertically extending columns of header members which header members extend into the structural backfill from a front face of the wall. The header members have bases which rest upon an underlying header member and have front and rear post portions which extend up to the base of an overlying header member. Front ends of the header members have arms which extend outward and upward at the face of the wall at locations which are in front of the compacted structural backfill. A plurality of horizontal stretcher members extend between the columns of header members at the front face of the wall and are supported by the inclined arms of the header members. The stretcher members are spaced apart from header members other than the particular header members which support the stretcher member. A plurality of vertically spaced horizontal layers of geosynthetic mesh reinforcement extend between the columns of header members and extend backward therefrom within the backfill. The layers of geosynthetic mesh reinforcement have upturned forward ends which extend upward at the front of the compacted backfill and then extend back into the backfill. Planting soil is disposed between the stretcher members and the upturned forward ends of the layers of geosynthetic mesh reinforcement and forms tiers of planting soil at the front face of the wall.
In still another aspect the invention provides a retaining wall having a plurality of spaced apart vertical columns of stacked header members which extend into backfill material and a plurality of stretcher members which extend horizontally between front portions of the header members. The header members have flat top surfaces and flat bottom surfaces. A plurality of pins extend vertically from holes in the top surfaces of the header members into holes in the bottom surfaces of overlying ones of the header members and fix the positions of the header members relative to each other during construction of the wall.
The invention provides a modular retaining wall construction in which the horizontal component of load force in the backfill is resisted by layers of geosynthetic mesh reinforcement within the backfill rather than by the stretcher members which form the face of the wall. Load force on the stretcher members is further minimized as the stretcher members are not contacted by overlying header members and thus need not provide support for overlying structure. Consequently the stretcher members may be thinner than would otherwise be required and may be spaced outward from the front surface of the compacted backfill. This provides a very sizable space between the stretcher members and the front of the backfill which space is filled with relatively loose topsoil or the like. Broad tiers of the topsoil are exposed at the tops of the stretcher member. These conditions greatly facilitate planting and cultivation of plants on the face of the wall. In the preferred form of the invention, the header members are interlinked by vertical pins which fix the positions of the header members relative to each other to maintain the desired inclination of the front face of the wall during construction of the wall.
The invention, together with further objects and advantages thereof, may be further understood by reference to the following detailed description of the invention and by reference to the accompanying drawings.